How 3D Printing Is Used In The Mold Manufacturing Industry

How 3D Printing Is Used In The Mold Manufacturing Industry

3D printing has had a major impact on manufacturing across many industries, and the mold-making sector is no exception. Also known as additive manufacturing, 3D printing offers game-changing capabilities for mold production that enable faster turnaround, design flexibility, and cost efficiency versus conventional methods.

In this comprehensive guide, we’ll examine the key benefits 3D printing brings to mold making and the various applications where it excels. We’ll cover the popular techniques used, accuracy and surface finish considerations, suitable materials, and how 3D printing integrates into the overall mold manufacturing workflow. With the right approach, 3D printing can dramatically accelerate and enhance mold production.

Benefits of 3D Printing for Mold Making

There are several major advantages 3D printing offers for mold tooling:

Rapid Prototyping – Prototype molds can be 3D printed in hours/days rather than weeks for machining. This enables faster design verification and testing.

Complex Geometries – Organic and complex shapes are easily printed compared to needing extensive CNC programming and machining.

Conformal Cooling – Optimized conformal cooling channels are 3D printed into the mold for maximum efficiency.

Design Freedom – Almost no constraints on mold design to work around typical machining limitations.

Low Volume Production – Great for short production runs where machining molds would be too time-intensive and costly.

Hybrid Molds – Combining 3D printed and machined components provides the ideal balance of speed and strength.

Cost Efficiency – Printed molds cost a fraction versus CNC machined molds for prototyping or bridge tooling.

These capabilities make 3D printing an appealing option for mold makers looking to deliver high-quality molds faster and at lower cost to their customers. The technology has reached the point where printed molds can even handle short manufacturing runs.

Popular Techniques for 3D Printing Molds

Several 3D printing technologies are well suited for mold tooling:

Stereolithography (SLA) – Uses a laser to selectively cure liquid photopolymer resin layer-by-layer. Known for smooth surface finish.

Digital Light Processing (DLP) – Similar to SLA but cures full layers at a time for faster build speeds.

Fused Deposition Modeling (FDM) – Extrudes heated thermoplastic filament in layers. Lower resolution but has good strength.

Selective Laser Sintering (SLS) – Uses a laser to sinter powdered material together. Wide choice of thermoplastic and metal materials.

Direct Metal Laser Sintering (DMLS) – Prints fully dense metal parts from metal powder sintered by a laser.

PolyJet – Jets ultra-thin layers of photopolymer for excellent detail and surface finish. Some multi-material capabilities.

SLA, DLP, and PolyJet are valued for the extremely smooth surface finish they can achieve on printed molds. This allows the mold to produce parts with high-quality surface finish straight from the printer.

FDM and SLS offer a more limited finish but provide good mold strength and thermal resistance for longer production runs. DMLS can print sturdy metal molds capable of thousands of injections.

Material Considerations for Printed Molds

Choosing the right material is crucial for printed molds. Key considerations are heat deflection temperature, elongated stability under injection pressure, surface finish, dimensional stability, chemical compatibility, and strength.

For prototyping, SLA resins provide excellent resolution, surface finish, and quick turnaround. Low-volume production is possible with around 10-100 shots before heat or pressure degradation.

Engineering plastics like ABS, PC, and nylon excel for bridge tooling with up to tens of thousands of shots. These production-capable thermoplastics offer good longevity under injection pressure and heat deflection over 100°C.

Metals like aluminum, maraging steel, nickel alloys, and tool steels printed by DMLS offer the highest mold strength. They withstand thousands of injections while maintaining excellent dimensional accuracy.

For the best results, mold makers should select a 3D printer and material tailored to each application’s specific accuracy, finish, and durability requirements.

Achieving High Accuracy and Surface Finish

Mold makers must meet tight tolerances and surface finish requirements that allow the molded parts to accurate. Here are useful techniques for attaining precision with 3D printing:

• Utilize the highest precision printer within budget constraints. SLA and PolyJet offer incredibly smooth surfaces around Rz 2-4 microns.
• Choose materials with low shrinkage and good stability like ABS, PC, or metal alloys.
• Optimize print orientation to minimize stair-stepping effects on visible faces.
• Use fine-layer resolutions. Layer heights of 50 microns for SLA and 20-40 microns for metal printing are typical.
• Perform any required machining, grinding, or polishing on critical surfaces post-print.
• Apply specialty coatings to further enhance surface finish while protecting against injection pressures.

With the right process planning and post-processing, 3D printing can achieve surface roughness and geometrical accuracy suitable for molding high-quality plastic and even metal parts in short runs.

Integrating 3D Printing into the Mold-Making Workflow

While 3D printing brings many benefits, mold makers must intelligently integrate the technology into their overall mold manufacturing process chain and economics. Here are the best practices mold makers should follow:

• Assess each project on a case-by-case basis as to where 3D printing brings advantages over CNC machining based on customer requirements.
• Use 3D printing for rapid prototyping of the mold design to get customer feedback early before the final tool design.
• Utilize 3D printing on complex geometries that are time-consuming or impossible to machine.
• 3D print conformal cooling channels into the mold for optimal temperature control and cycle times.
• Combine 3D printed mold components with traditionally machined surfaces for the best of both methods.
• Plan design and print orientation to minimize post-processing requirements after print.
• Validate 3D prints dimensionally and make any adjustments prior to mold trials.

With experience, mold makers learn how to best leverage 3D printing’s capabilities while minimizing its limitations compared to CNC machining. Blending both technologies is the ideal approach.

Mold Industry Use Cases Showcasing 3D Printing Benefits

Here we highlight real-world examples of companies achieving significant improvements in mold making from adopting 3D printing:

• Protolabs developed proprietary processes for printing durable injection molds in days instead of weeks. Their customers include BMW and Medtronic.
• Hobbyists printed molds at home to launch new products, validating designs before committing to CNC mold tools.
• Small batch manufacturers use low-cost printed molds for tens of parts as an alternative to expensive CNC machined tools.
• Hybrid molds combine the high strength and wear resistance of DMLS metal components with machined aluminum injection faces.
• Conformal cooling channels 3D printed into molds reduced injection cycle times by over 50% for consumer product companies.
• Automotive company 3D prints prototype molds with tuned properties to simulate the performance of the final production mold.

These applications demonstrate the immense value 3D printing can provide for shortening development times, lowering costs, and enabling new mold geometries not feasible with other methods.

The Future of 3D Printing in Mold Making

3D printing will only become more capable and integrated into mold manufacturing in the future. Here are some exciting developments on the horizon:

• Hybrid additive/subtractive machines that combine printing and milling for complete automated mold production.
• New materials with properties tailored specifically for molding such as extreme hardness, heat resistance, and longevity.
• Improved printers with larger build volumes and multi-material capabilities will expand possibilities.
• The software will optimize print tool paths and conformal cooling layouts to maximize mold performance.
• Automated post-processing methods will improve surface finish, dimensional accuracy, and material properties.
• Aerospace and medical industries will increasingly adopt 3D printing for plastics and metal injection molding applications.

The competitive advantages 3D printing confers will make it ubiquitous across the mold-making landscape in the coming years as the technology rapidly advances.

Conclusion

This overview looked at the game-changing benefits 3D printing brings to the mold-making industry. Its abilities to create complex geometries, quickly iterate designs, and reduce lead times and costs versus CNC machining make it highly appealing for a growing portion of mold tooling applications. With mold makers embracing the capabilities of printed bridge tooling and hybrid molds, manufacturers can bring products to market much faster and more affordably than in the past. We expect 3D printing to digitally transform mold-making in the years ahead.